The number of animal models for the study of long-term hypertension and its concomitant cardiac hypertrophy and failure are limited. This application is directed toward the development of a naturally occurring primary essential hypertensive model in the dog. The goal of the project is to breed a colony of dogs that develop primary essential hypertension and determine whether this trait is due to a simple gene or whether it is polygenic. The dogs will be checked to determine age of onset of hypertension and the progression of the disorder. With echocardiographs we will determine time of transition to cardiac hypertrophy and the development of cardiac failure. We will analyze stored plasma, urine and serum samples for renins, aldosterone and catecholamines and correlate levels with age and onset of hypertension. The long-term goal is to make this trait in dogs availabe to qualified investigators.